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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-03-23 19:23:10 -0500
committerGustavo A. R. Silva <gustavo@embeddedor.com>2020-04-18 15:44:56 -0500
commit16c3380f8c2e7ed3d75a30776a89aabf5512027a (patch)
tree5f926d76a39a565f5e3245a1fef20077ae3ff2d4 /include/linux/swap.h
parent5c91aa1df00ec4fa283c35e92736392df3137d81 (diff)
swap.h: Replace zero-length array with flexible-array member
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Diffstat (limited to 'include/linux/swap.h')
-rw-r--r--include/linux/swap.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/swap.h b/include/linux/swap.h
index b835d8dbea0e..e1bbf7a16b27 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -275,7 +275,7 @@ struct swap_info_struct {
*/
struct work_struct discard_work; /* discard worker */
struct swap_cluster_list discard_clusters; /* discard clusters list */
- struct plist_node avail_lists[0]; /*
+ struct plist_node avail_lists[]; /*
* entries in swap_avail_heads, one
* entry per node.
* Must be last as the number of the